The present invention relates to a portable information terminal, particularly, relates to a personal portable information terminal constituted by a PC card type which is driven by a built-in battery.
Recently, high performance and down-sizing have been rapidly developed in computers and peripheral apparatuses. As a result, conventional desk-top type information terminals are also tended to be directed to miniaturization which is convenient for portable.
For example, recently, personal portable information terminals (below, xe2x80x9cportable terminalxe2x80x9d) which are called xe2x80x9celectronic notebookxe2x80x9d, xe2x80x9cpalm-top computerxe2x80x9d, xe2x80x9cpersonal digital assistant (PDA)xe2x80x9d, etc., have been produced.
In this case, the above PDA represents a personal information apparatus which can be easily carried, and comprises a pen-input function, a data communication function, etc., based on functions contained in a conventional notebook (a notebook made of paper), such as a schedule management, an address book, a memo-randum, etc. In the market, there are well-known types, i.e., a xe2x80x9cNewtonxe2x80x9d published on 1993 from Apple Co., Ltd. in U.S. and a xe2x80x9cZaurusxe2x80x9d from Sharp Co., Ltd. in Japan.
In the above portable terminal, a software which is called xe2x80x9cPersonal Information Manager (PIM)xe2x80x9d and executes schedule management, an address book, a telephone book, a memo random, etc., has been already installed, and comprises a data searching functions and a data transmission/reception function by connecting an external apparatus, so that the portable terminal has merits which are not contained in the conventional notebook (i.e., a notebook made of paper).
As mentioned above, the PIM is a tool for managing personal information, and is a kind of software for executing the schedule management, the address book, a project management, etc. Further, the PIM may represent a portable terminal itself having functions as well as the electronic notebook, the palm-top computer, the PDA, etc.
In the above mentioned conventional portable terminals, a key board, which is in general used in a personal computer or a word processor, is eliminated in order to attach importance to portability, and another input means is combined thereto instead of the keyboard.
As the above input means, the following methods are used in general.
(1) a method for arranging a small number of input keys, and inputting predetermined instructions based on sets of two or more input keys;
(2) another method for displaying a software keyboard on a display having a touch panel, and inputting instructions through the software keyboard; and
(3) still another method for inputting characters with handwriting on the touch panel, executing character recognition, determining and executing an input instructions.
As mentioned above, although the conventional portable terminals have various input means, these input means have various bad handling operations when using them. That is,
(1) When inputting instructions by a user, characters must be input through a small input key one by one by using a pen or finger, so that there are problems in which input operations become complicated and a lot of time is required when inputting characters.
(2) In the method for inputting characters with handwriting on the touch panel, there are problems in which a recognition rate of characters becomes insufficient and a lot of time and patience are required for handling many data.
(3) Further, in the conventional card type portable terminal, although a button type lithium battery is usually utilized in order to realize a thin terminal, there are problems in which a battery capacity is insufficient for power consumption in the CPU and the liquid crystal display panel so that a lifetime of the battery becomes short and it is impossible to continuously use it for a long time.
The object of the present invention is to provide a new personal portable information terminal having a PC card type which can resolve the above mentioned conventional problems and, according to the present invention, in actual use, it is possible to realize ease of input of instructions and data from the user and good portability, and to achieve long operations by using a battery having a small capacity.
In accordance with the present invention, there is provided a portable information terminal at least including a programming ROM, a work RAM, a data storage memory, an input key, a liquid crystal display panel, a liquid crystal driving control circuit, a built-in battery, and a central processing unit which is operated by using the programming ROM and the work RAM and displays data in the data storage memory on the liquid crystal display, including:
a switching control circuit for outputting a switching signal in accordance with an input signal from an external computer apparatus connected to the portable information terminal;
a control signal switching circuit which switches an address bus, a data bus and memory control signal lines which are connected to the central processing unit, to an address bus, a data bus and memory control signal lines which are connected to the external computer apparatus, in accordance with the switching signal, in order to access the data storage memory from the external computer apparatus; and
a PCMCIA standard female connector which is connected to the external computer apparatus;
and further including:
a serial signal switching circuit which switches a PCMCIA bus control signal to a serial signal in accordance with an input signal from a serial interface device connected between the portable information terminal and the external computer apparatus; and
a recognition circuit which recognizes the serial interface device.
As a preferred embodiment, a portable information terminal further includes a power source switching circuit for switching a power source signal between the built-in battery and the external computer apparatus, when the switching signal is input thereto.
As another preferred embodiment, a portable information terminal further includes a power source switching circuit for switching a power source signal between the built-in battery and the serial interface device in accordance with the input signal.
As still another preferred embodiment, the serial interface device includes at least a serial connector, a voltage transformer, a PCMCIA standard male connector, a waveform generating circuit, a power source, and two sets of input/output signal terminals;
the portable information terminal having a PCMCIA female connector is connected to one of the two sets of input/output signal terminals, and the external computer apparatus is connected to the other of two sets of input/output signal terminals; and a serial signal is transmitted/received between the portable information terminal and the external computer apparatus.
As still another preferred embodiment, a serial signal having different data bit length and transfer rate between an input signal and an output signal is transmitted/received between the portable information terminal and the external computer apparatus.
As still another preferred embodiment, the liquid crystal driving control circuit, the switching control circuit and the control signal switching circuit are integrated to one chip semiconductor in order to constitute an ASIC.
As still another preferred embodiment, the liquid crystal driving control circuit, the switching control circuit, the control signal switching circuit, the serial signal switching circuit and the recognition circuit are integrated to one chip semiconductor in order to constitute an ASIC (Application Specific Integrated Circuit).
As still another preferred embodiment, the data storage memory comprises an SRAM or a flash memory.
As still another preferred embodiment, the programming ROM comprises a mask ROM or a flash memory.
As still another preferred embodiment, the built-in battery comprises two lithium coin batteries which are connected in series.
As still another preferred embodiment, the liquid crystal display panel comprises an STN monochrome reflection panel or an STN color reflection panel.
As still another preferred embodiment, a top cover is arranged on the display side of the liquid crystal display panel, a circuit substrate is arranged at the rear side of the liquid crystal display panel, circuit parts are arranged on the surface opposite to the liquid crystal display panel of the circuit substrate, and a bottom cover is arranged in order to protect the circuit parts, so that the portable information terminal is formed of five layers.
As still another preferred embodiment, sizes of an outer and a thickness of the portable information terminal are defined based on a PCMCIA standard type II.